All right. Thank you, ladies and gentlemen. Please be seated. Mr. Matheson, would you resume the witness stand, please. Mr. Blasier, you may continue with your cross-examination.
Mr. Matheson, I want to ask you some questions about contamination. Now, do you agree that if there are problems with the collection, packaging or handling or analysis of evidence that contamination can result?
If the items are handled in such a way that allows them to come in contact with things that they shouldn't, with other pieces of evidence or with things in the environment that they shouldn't, yes, they can create contamination.
Now, contamination, that term is not--well, tell me what it means to you in the context of serological testing and DNA testing.
It would deal with having something introduced into the sample that doesn't belong there, that it is not part of the sample as it was deposited.
Now, no one has ever suggested to you, have they, that a clean blood sample from the particular person can change type because it gets dirt on it, for instance? Has that ever been suggested to you?
The concept of contamination involves one biological material getting in contact with another, correct?
And the notion of contamination affecting test results deals with one biological sample from one source getting mixed or replaced by a biological material from another sample, correct?
I don't believe it is just limited to being mixed or coming in contact with other biological materials. You can get contamination of non-biologicals, too.
But a non-biological item is not going to change the blood type, for instance, of a blood sample, correct?
Well, are you saying that there are no circumstances where one biological material getting in with another can change the type of that material?
Depending on the degree of contamination, yes, it could change the results of the analysis.
Now, is it important to have procedures in place to prevent contamination in the collection, packaging, handling and analysis of evidence?
Do you feel that protections--additional protections are necessary when you are considering doing DNA testing such as PCR amplification?
I believe the only additional controls or process that would be necessary is that the person be aware that--that it takes a very small amount of sample to give a PCR result.
Well, I don't know, you know, as far as exact size or weight. I believe it is something you would have to be able to see when it comes to forensic analysis.
Is it your understanding that only biological material that you can see can be typed using PCR?
I'm saying when we are talking about blood samples, I am not aware of the fact that a blood sample that is invisible to the eye would be typeable by the procedures used in forensics.
I have never performed tests or anything on--you know, to determine the quantity.
During the years that you spent arranging and helping to set up your lab, you never learned anything about the quantities of DNA necessary for conducting tests?
I oversaw the process. I wasn't actually in there actually hands-on working with them establishing the procedures. I have heard over the years figures given as far as how much DNA is necessary to get a result. Off the top of my head right now I don't know what those are.
And a gram is about 15 hundredths of a pound, approximately one 454th of a pound, correct?
So if you took a pound of something and cut it up into 454 pieces and then took one billionth of one of those pieces, that is a nanogram, correct?
What is your understanding in terms of the minimum amounts of DNA required to do typing?
And is it your understanding that you can see one or two nanograms of DNA in a blood sample?
Far smaller than you need to do any kind of conventional serological testing, correct?
And can you tell me, in your lab, what procedures--procedures with respect to collection, packaging, handling and analysis of evidence have changed since you started doing DNA testing?
The only thing that has changed has been we have tried to maybe the people aware that it is a very sensitive test. The actual procedures themselves have not changed in that we still just use clean tools, we wipe them off with a dampened tissue or something like that, and avoid contact with other items.
Have you done any studies on whether the procedures that you use to collect serological samples for conventional serology are adequate to guard against contamination when you are considering doing DNA testing?
Now, that chart indicates twenty nanograms is approximately the size of a pin head. Is that your understanding or is it your understanding that two nanograms is the size of a pin head?
Well, I'm not talking specifically about quantities and there you are referring to I'm assuming an amount of DNA. Two nanograms or even 20 nanograms of DNA would not be visible.
Did you say earlier, though, that you thought two nanograms in a blood sample would be visible?
I believe that--my understanding is that using the forensic technique the amount of DNA found in a bloodstain or something that you would be able to see, it would be very, very small, but you should be able to see it.
Mr. Blasier, do you want to move that exhibit down toward the end of the box so the other jurors can appreciate the comparison?
And do you know how many nanograms of DNA there are in a microliter or millionth of a liter?
Now, the technique that is used in your lab called PCR, I'm not going to ask you a lot of detailed questions about this, but basically involves taking a very small amount of DNA and multiplying it into a bigger amount? Is that an accurate rough description?
And just like the enzyme system that you were talking about yesterday have genotypes, DNA has genotypes as well, correct?
And it is the same kind of structure in the sense that we inherent half of our DNA from our dad and half from our mom, correct?
And it is the same kind of inheritance process that is going on that accounts for two different what are called alleles, one from each parent, correct?
So, for instance, in the EAP system that we were talking about yesterday, when you describe somebody as being a BA, that tells you that they got the B allele from one parent and the a allele from another parent, correct?
And in the PCR system, the genotypes work the same way in the sense that there are two numbers associated with any particular genotype, one which came from your father and one which came from your mother?
Now, in the EAP system that we were talking about yesterday, when you say that somebody is a B, what this really meant is that they got a B from both parents so in it is in essence a bb, correct?
Now, the DNA in a person's saliva, for instance, is the same as the DNA in their blood? You are aware of that, are you not?
And the tests that are run, PCR tests that you do in your lab, are incapable of telling the difference between DNA which comes from saliva as opposed to DNA which comes from blood?
Now, Mr. Goldberg asked you questions about DNA floating in the air and I believe you said you weren't aware of that happening, correct?
Well, you are--if you don't cover your mouth open and you sneeze in the open air, some of what comes out is going to be saliva and other constituents and that is going to have cells in it which is going to have your DNA in it.
If you are standing over something like a podium and dead skin cells fall off your skin, that has DNA in it as well, does it not?
What I've heard of on that is to wipe down the counters of a work area, then extract that wiping and amplify it and analyze it for DNA types.
And wiping down a counter which may not have anything apparent to the eye on it might have DNA in it, correct?
We are getting there. We are real close here because this is specific PCR testing and this person was not presented as a PCR witness for the Prosecutor. I think you have established what the issue is here. Proceed.
Can saliva from one person, if it gets in a bloodstain on the ground, result in the first person's DNA showing up in the bloodstain?
And if the bloodstain on the ground has deteriorated because of humidity or environmental conditions to the point where there is not a lot of DNA in it, and it is contaminated by saliva from perspiration, for instance, from somebody leaning over it, that person's DNA type would show up or could show up rather than the actual type in the blood, correct?
If as you say the original bloodstain had deteriorated completely to the point where you could not get any results from that, that's correct.
And the type of tests that you do are incapable of telling the difference in my hypothetical between DNA that comes from perspiration of the person standing up as opposed to the blood of the person who deposited it?
Overruled. I will allow this one issue, but I think we need to move on. Is that true, Mr. Matheson?
Now, Mr. Matheson, the amplification process that you go through when you do PCR tests involves taking a small amount of DNA and doubling it in what are called cycles, correct?
And that chart depicts that starting out with the very small amount and doubling it thirty times leads to a very large amount, correct?
Mr. Matheson, is it accurate that with PCR amplification there, we have been talking about in general terms, that if you have DNA from more than one source, the amplification process amplifies both sources?
And just like my example with saliva contaminating a bloodstain, you can have flakes of blood from one stain if it gets on a second stain that can will contaminate the second stain as well, correct?
And if it is in sufficient quantity to amplify, if the second stain is amplified, the components that came from the first stain gets amplified as well, correct?
It gets amplified as well, but it depends on--there is a point at which in the dilution or if you have significantly more of one type of DNA than another, the one that exists in the larger quantities may be the only one that you see.
Mr. Matheson, with respect to your last answer, would you agree that the manner in which in terms of final quantities of DNA that you get with the amplification I described is really beyond your area of expertise?
Now, you have testified, I believe, that you do not consider it necessary, when dealing with biological stains that might be subjected to DNA testing, to change gloves between each item that you handle; is that correct?
Not just as a matter of rule to automatically change it between each item, that's correct.
Do you remember--actually it is the same visit we were talking about before on August 26th to your lab by various representatives of the Defense.
Do you remember the date when Mr. Ragle, Mr. Neufeld, Dr. Lee and several others came to the lab for a tour that you talked about before?
Okay. And at that particular meeting they examined some items of evidence, did they not?
I don't recall. For that I would like to take a look at if I have any notes on that date.
Well, counsel, let's move on rather than have the witness search through his notes. Let's focus on what we need to develop.
Is that the procedure that you use when representatives of the Defense are there?
That was--if in fact I did that, and it is entirely possible that I did, yes, we were being hyper sensitive at that point to the handling of all these items.
KEY QUOTEWhen you are doing handling of items in the privacy of your lab with no Defense people watching you, you don't follow that procedure, correct?
I do not change my gloves after every time or change the paper every time unless there is some indication, such as the item coming in contact with the paper or there being a chance of transfer the evidence.
KEY QUOTESo it is only if you become aware that you may have touched something that it becomes important to change gloves?
There is a chance that you are going to cross contaminate, yes, at that point you would want to change gloves.
Now, your laboratory has an extensive division order in the field manual that we have been talking about and I will refer you to page 125 if you still have that there.
You have an extensive procedure that is followed with respect to handling possibly contaminated evidence in the lab, correct?
And the reason why you want to be careful about that is because you may ingest something of an infectious nature from some evidence that you might have collected, correct?
All of the controls are in place to prevent the operator of coming in contact with the blood, that's correct.
Because if you come into contact with it, it may come into your system and make you sick?
The same kind of transfer can happen with DNA from biological samples, can it not, with the exception that it doesn't make you sick?
The same kind of transfer in terms of getting something on your skin or on your glove or on your clothing can happen with respect to small particles of DNA or biological material that contains DNA as with infectious disease materials, correct?
You can--if what you are saying is can these items still come in contact with your clothing or whatever and not make you sick, then yes.
And if they come into contact with your clothing and your gloves, they can then come in contact with other items that you might touch, for instance, other evidence items?
I think so. If--the whole idea of wearing these things is if something happens to get on you, it doesn't come in direct contact with your skin. If you are wearing gloves, then what would have come in contact with your skin has now come in contact with your gloves, and then if you use those gloves to handle something else, the potential exists for transfer it, yes.
Now, when you are handling biological material that may be subject to DNA testing, you do not use the same precautions that you use when handling materials that you may suspect have the potential of having infectious diseases, do you?
Well, we are still wearing gloves and we are not going with those gloves in areas where we shouldn't. If there is something on them, then we change them and put on clean ones.
After you handle biological material in the evidence processing room on that table that we saw in the picture, do you clean the table?
We have--actually beyond that, the items are wiped down with a solution of water and bleach.
That if there is any residue left on that counter, when you are done with your work, you clean it off and it is not left there for somebody unsuspecting to come along and become contaminated by it.
Do you recognize that you can get a contamination with your evidence materials from things that you can't see?
I still feel that particularly if you are dealing with, say, a bloodstain swatch or something like that, that if the quantity of material that is going to get on it is so small that you cannot see it, then it is not likely to cause any contamination of that item.
Have you studied the procedures used by any other laboratories that do DNA analysis with respect to the issue of cleaning tables after each item is examined?
Have you examined any other laboratories that do DNA testing with respect to whether you should change gloves after handling each item?
Have you studied any other laboratories that do DNA analysis with respect to how you should clean your tools between handling samples?
Andrea Mazzola testified that she uses on occasion serrated tweezers. That is accurate?
I did hear that and I believe she said that both serrated and non-serrated were available.
Okay. Serrated tweezers are tweezers that have little groves in the end of them so that it is easier to hold the swatch, correct?
What did you understand the distinction she made between when she uses serrated tweezers and when she doesn't?
The way I heard it, because I was concerned, was that they were available in the kit, but I never heard her saying that she used serrated tweezers for blood collection. That would be inappropriate.
Do you have anything in writing anywhere to tell your people that the serrated tweezers in the kit should not be used to collect biological evidence?
Do you know whether that has been communicated to the people that work for you in any fashion at all?
I can't specifically say. I--I pass it on to the people who I am teaching out in the field and it may be, though I'm not sure, part of training that they have received as far as biological evidence.
Is it your understanding that wiping off a pair of tweezers with a chem wipe--which is I think the procedure you described, correct?
--with a dampened chem wipe is sufficient to clean off potential biological material that may have been left over from earlier evidence?
Have you done any studies to demonstrate whether that is an effective way to completely remove DNA from earlier samples?
In a way we are constantly doing a study on that because it is the same process used for our controls.
Did you run any particular studies designed to just find out whether that works the way you think it does?
Are you aware of any scientific articles that say that that is all you need to do to clean your tools between handling items?
Have you evaluated any other DNA laboratory anywhere with respect to that issue to find out what procedure is used to clean the tools that is used to handle the evidence?
Now, I think you testified on direct, you were asked some questions about what are hot topics and what are not hot topics. Do you remember that line of questioning?
You were being asked some questions about collection of evidence in terms of whether particular topics were big topics in the forensic community or not?
And is it your opinion or your understanding that the topic of the collection of evidence for purposes of DNA testing is not a controversial topic in the forensic community?
I believe we were specifically talking about the part that references the actual swatching and picking up. There has not been an awful lot of discussion that I have heard regarding whether you should use water or alcohol or whatever to clean your tweezers. I mean, it is just not a big thing that has been discussed.
Do you recall an occasion, I believe it was January 18, when I visited the lab with Mr. Scheck and a few other people?
And we looked at I believe there were two different evidence kits that were put on the table and everything was taken out to look at. Do you recall that?
Well, they weren't two different kits. They kind of work together. It isn't like you would use one or the other one to take out to the scene. In a situation like that you would grab both of those kits.
Do you remember how--and there were extensive pictures taken of all there, weren't there?
Do you remember how we found a scalpel that had been in a sealed container that actually was left open and put back in the kit?
If you are going to use a scrape method rather than a--the swatch that we have described, yes, you do occasionally use a scalpel.
And sterile scalpels come in sealed containers that when you want to use them you open it up and you use it and you throw it away, correct?
Would it be inappropriate to take one of those scalpels and put it back in an evidence kit after it has been used?
I believe there were swabs in there. I don't specifically remember showing them.
And when you open those bags, you use everything you need to use and then you throw them away, don't you?
When you don't use them up, do you put the unused swabs that have already been opened back in the evidence kit?
They are still in their original packaging, yes, but they are returned to the kit.
Do you remember when we were there, Michele Kestler started to put those back in the kit and you grabbed them and threw them away?
Mr. Matheson, let me show you a document, "guidelines of preservation and collection of DNA evidence by the FBI." are you familiar with that?
I don't remember all the specifics in it or if we follow each and every instance that is in here.
Now, this is a document, that is put out by the Federal Bureau of Investigation or the United States Department of Justice, correct?
And these are guidelines that they have put out for the purpose of giving guidance to crime laboratories like yourself on the proper way to collect and preserve evidence if you are going to do DNA testing, correct?
And do you accept the FBI as an authority on the proper way to collect evidence for preservation--I'm sorry, collect and preserve evidence for DNA testing?
I believe that they are an organization that knows quite a bit about all that and I would take into account what they have to say.
Do you believe that you should videotape a crime scene to show the relative position of all pieces of evidence?
Wait a minute. That is not what it says in this document and I would object to the Defense reading from it.
And loud commentary over here as well. Touche. Both sides will be sanctioned. All right. Proceed.
Let me refer you to page 5. I don't want to misquote anything. Would you agree that the FBI guidelines state that: "crime scenes should be videotaped with the relative position of the items of evidence before they are touched or moved."
Have you considered the FBI's guidelines in formulating your own opinions on the proper way to collect and preserve evidence for DNA testing?
Have you considered the FBI's guidelines, the provisions with respect to identifying evidence items that is collected--that are collected?
I would have to make reference or be referenced to where it is at. Like I said, I have read it, but I have not committed to memory all the different aspects of it.
All right. Can you tell me--let's look at page 6. The provisions with respect to collecting reference blood samples, do you follow those guidelines.
It is not relevant. They didn't collect the reference blood sample; the Coroners did.
Do you know whether the Los Angeles Police Department follows the FBI guidelines with respect to that?
When you get a reference sample from the police department how many tubes are there in it, generally?
Do you follow item no. 4 at the bottom with respect to labeling specimens that are collected for analysis?
Mr. Matheson, did you participate in the preparation of the demo type with Andrea Mazzola swatching a stain?
Did you have involvement at all prior to the time that was made, in terms of anything involving that demo tape?
The first time I saw it was after it was shown in this courtroom. Actually I saw bits and pieces of it while it was being shown, but in its entirety after it was shown in the courtroom.
Did you notice in that video that when she collected a control stain that the moisture from where she was collecting the control migrated into the bloodstain itself?
She wasn't collecting blood evidence at that point; she was collecting the control.
Is that an acceptable technique to use when you are collecting a control for a sample that you are then going to collect?
It would be nice if they didn't come in contact, but I don't believe it is going to have any effect.
Okay. Did you notice the number of times she rubbed her hand on the ground when you saw that the first time?
Is that an examine technique, when you are collecting blood evidence, to rub your hand on the ground?
Well, in that she wasn't then rubbing her hand on the evidence, I don't see where that makes a difference.
Did you hear her testimony where she said she wasn't even aware that she had done that?
Did you notice the number of times in that video that Miss Mazzola took her tweezers and turned them inward in the palm of her hand?
As long as they are not coming in contact with where the evidence is going to be handled I don't see that is a problem.
Well, it is not okay if it is touching an area which is dirty and is not cleaned prior to being used again.
If they are not aware that they are touching the ground, is it your belief that they are going to be aware if they happen to touch some evidence?
Now, Mr. Matheson, I want to ask you some questions about the blanket. Do you have that in mind?
Do you believe that it is a proper procedure at a crime scene where you are collecting biological evidence to bring something from outside the crime scene, such as a blanket, and put it on the evidence?
And the reason that is inappropriate is because you can inject trace evidence that wasn't in the crime scene into the crime scene by doing that, correct?
And a blanket, such as a thermal blanket, is an excellent collector of trace evidence; is it not?
I would say that, yes, a blanket has a very good chance of picking up trace evidence.
And if a blanket is thrown out over a scene it has a potential of depositing that trace evidence on the scene, correct?
If the blanket is taken and thrown out or shaken out or something like that, that would allow what was on it to be spread out throughout the scene and that was to land on something, you have the possibility of contamination.
How about if it was just put down on something, trace evidence could come off of it, couldn't it?
If it was carefully laid down you have the potential of something falling off of it directly under it, yes.
Should your criminalists be alert to foreign things, such as a blanket, being brought into a crime scene in terms of their processing of that scene?
I would think that that is something that you should be aware of, that it is occurring.
Do you know whether Dennis Fung ever made any inquiry or Andrea Mazzola ever made any inquiry as to where that blanket came from?
Would you expect a competent criminalist to make some kind of inquiry as to where a blanket in the middle of the crime scene came from?
Would you expect a capable, competent criminalist seeing a blanket in the middle of a crime scene with blood on it to collect that?
I can speak for myself at this point. If I arrived at a scene where a blanket was heavily covered with blood and was advised that that was over the victim, I would not necessarily collect it.
To your knowledge is there any forensic reason or legitimate forensic or investigative reason for putting a blanket on a body at a crime scene?
Mr. Blasier, I need to change Court reporters at 3:00, so perhaps this would be a good time to look for that.
Ladies and gentlemen, we are going to take a brief recess for ten minutes and change Court reporters. Please remember all my admonitions to you. And have the jury step back in the jury room. And Mr. Matheson, you can take a ten-minute break.
That was--if in fact I did that, and it is entirely possible that I did, yes, we were being hyper sensitive at that point to the handling of all these items.
The DNA test cannot tell the difference, that's correct.
From a forensic standpoint? There is no reason.
I do not change my gloves after every time or change the paper every time unless there is some indication, such as the item coming in contact with the paper or there being a chance of transfer the evidence.
Touche. Both sides will be sanctioned.